The invention relates to a drum cutter-loader machine for underground mining whose two cutting drums are each mounted on individual support arms which are separately connected by gearing to individual driving motors arranged on the side of the support arms opposite their drums. As to each of the support arms, the motor is arranged in a protective housing which in turn is fastened to the support arm. Pressure cylinders are provided so as to be able to swivel the arm about an axis mounted on the machine body which is parallel to the mine floor and in the direction of the coal face side.
Equipping drum cutter-loader machines with a swivelling arm axis which is fixed in front and on the top of the machine body and fixed parallel to the mine floor at right angles to the direction of travel of the machine forms part of the existing prior art, as German Patent No. 26 12 671 illustrates. In one form of the prior machines a support arm to which the cutting drum is connected also carries a driving motor on the side opposite the drum side which is situated parallel to the swivelling axis of the support arm. The driving motor is situated inside a protective housing which is fastened to the side wall of the support arm. The housing at its end extending in the direction away from the support arm is supported by a shoulder that forms a swivelling axis on the machine body. A swivel cylinder, which initiates the pivotal movement of the support arm, acts through a rocking lever. In order to reduce the overall height of the machine, the machine body is provided at each of its two ends with a cavity which serves to accept the swivel cylinder, and which is situated inside the plane of movement of the rocking lever and emerges from the floor area of the machine body.
Moreover, it is also known in the case of drum cutter-loader machines which are suitable for long-front mining, to equip the support arm of the cutting drum with two swivel cylinders, as British Patents No. 11 32 741 illustrates. Both swivel cylinders are mounted in an articulated manner on the support arm, which is swivelled about an axis which is pointed towards the coal face side. In this design, since the two swivel cylinders are situated above the machine body and the support arm, they increase the overall height of the coal-cutting machine.
In both of the above cases the arm which carries the drum i.e. breaking-down tool is fixed to the machine body in the immediate vicinity of the coal face. Consequently, the adjusting cylinders are also situated in this area of the machine body. As a result, it is not possible to drive the machines described in the first-mentioned publication with a cog rack or pin-toothed rack of the long wall conveyor means which is arranged on the coal face side, because the swivel cylinders due to their mounting arrangement, particularly in the case of low-constructed cutter-loaders, would collide in their elevating motion with the cog rack or pin-toothed rack. On the contrary, machines described in the last-named publication can be used only in seams of great thickness.
A coal-cutting machine which is provided with a swivel frame carrying a rotating cutter bar is also known through German Registered Design Patent No. 15 14 914. This swivel frame is mounted on a slide frame so as to be swivellable about a horizontal axis which is pointed towards the coal face side, and is pivoted by pressure cylinders into a working position which in turn allows the cutter bar to adopt its working position. Two or more of these pressure cylinders are combined into one block and are arranged one behind the other with a small overall width in the longitudinal direction of the coal-cutting machine in which their pistons can be actuated simultaneously.